qemu/atomic.h: add #ifdef guards for stdatomic.h

Deep inside the FreeBSD netmap headers we end up including stdatomic.h
which clashes with qemu's atomic functions which are modelled along
the C11 standard. To avoid a massive rename lets just ifdef around the
problem.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200326170121.13045-1-alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed